This invention relates to grinding machines. More particularly the invention relates to a semi-automatic grinding machine for sharpening drill bits of the type used for mining coal known as miner bits.
Miner bits comprise a carbide tip that is inserted into a steel carrier. The cutting tip of the bit is conical and wears during use. Heretofore, it has been more economical to dispose of used miner bit cutters rather than sharpen them, first, because the conical tip could not be accurately sharpened by hand, and further, because the tip often wears down to such a degree that interference between the carrier and a grinding wheel used to grind the tip is created precluding grinding of the carbide tip at the proper angle. This has resulted in large numbers of otherwise good miner bits being discarded which is economically wasteful.